I’ve heard the ti89 is highly recommended in this sub, but which one? The old one or the ti89 titanium?

For context I’m an Electrical Engineering student and I’m taking more major heavy classes next semester. I currently have a ti83 and ti84+CE (mainly just took them from family members who don’t use them anymore). I’ve heard the ti89 is better than the ti84 due to its ability to solve systems of equations better than the ti84. My question is does this work on both the regular ti89 the same way it works on the ti 89 titanium?